Grain milling device

ABSTRACT

A milling device for grinding grains, cereals and the like to preselected fineness includes a stationary, laterally disposed upper stone which is provided with a downwardly opening conical aperture therethrough and a flanged skirt, concentric about the conical opening, which is joined to a flat, horizontal, outer annulus. A rotatable lower stone includes a flat plate opposed to the outer annulus of the upper stone to which a conical projection is joined eccentrically with respect to the axis of rotation. The conical projection is received within the conical aperture, forming a non-uniform cavity therebetween in which primary cracking of the grain occurs. The stones are provided with opposed spiral grooves which capture the grain and feed it from the conical portions down to the opposed horizontal portions where the cracked grain is reduced to powder or granular size. The upper stone is slidably mounted on vertical posts, and is adjustably spaced apart from the lower stone by a manually rotated ring independently secured to the posts and including annular camming portions which impinge on the upper stone.

United States Patent [191 Musgrove et al.

[4 1 Dec. 16, 1975 GRAIN MILLING DEVICE Calif.

[73] Assignee: Emcee Corporation, San Leandro,

Calif.

[22] Filed: May 24, 1974 [21] Appl. No.: 473,203

[56] References Cited UNITED STATES PATENTS 10/1870 Buchholy 241/248 X 8/1945 Erickson 241/257 R X 2,937,815 5/1960 Eirich et al. 241/257 R 3,533,568 10/1970 Archer et al 241/202 3,754,716 8/1973 Webster 241/290 X FOREIGN PATENTS OR APPLICATIONS 111/1894 United Kingdom GREAT BRITAIN 5/1963 Germany 241/257 R Primary Examiner-Granville Y. Custer, Jr. Assistant Examiner-Howard N. Goldberg Attorney, Agent, or Firm-Harris Zimmerman [57] ABSTRACT A milling device for grinding grains, cereals and the like to preselected fineness includes a stationary, laterally disposed upper stone which is provided with a downwardly opening conical aperture therethrough and a flanged skirt, concentric about the conical opening, which is joined to a flat, horizontal, outer annulus. A rotatable lower stone includes a flat plate opposed to the outer annulus of the upper stone to which a conical projection is joined eccentrically with respect to the axis of rotation. The conical projection is received within the conical aperture, forming a nonuniform cavity therebetween in which primary cracking of the grain occurs. The stones are provided with opposed spiral grooves which capture the grain and feed it from the conical portions down to the opposed horizontal portions where the cracked grain is reduced to powder or granular size. The upper stone is slidably mounted on vertical posts, and is adjustably spaced apart from the lower stone by a manually rotated ring independently secured to the posts and including an nular camming portions which impinge on the upper 12 Claims, 8 Drawing Figures US. Patent Dec. 16, 1975 Sheet20f2 3,926,38

GRAIN MILLING DEVICE BACKGROUND OF THE INVENTION The art of grinding grain and cereal for foodstuff is ancient and seemingly well-developed. The traditional method employed a large millstone rolling in a circular path on a stationary stone, crushing the grain by sheer weight and reducing it to flour after repetitive passes. This process developed little heat, thus leaving most of the nutrients in the grain intact. However, the method required a great amount of energy for a small output, and was rather slow.

Modern milling techniques generally involve the use of parallel, opposed cylindrical metal rollers rotating at high speed to produce a high volume of flour at high production rates. However, the high rotational speeds of the rollers generate a great amount of heat which is transferred to the grain being processed, causing deterioration of the vitamins and other nutrients. Thus many individuals who are concerned about their personal nutrition shun the grains which are ground in modern fashion, preferring to pay a premium price for stone ground grains.

It is now recognized that grains naturally retain most of their nutrients while in the whole state, and that once the grain is ground into flour the nutrients rapidly deteriorate. Grains ground in modern food processing plants are often stored thereafter for long periods of time by distributors and retailers, much to the detriment of the well-being of the consuming public. There is, therefore, a need for a milling machine which will provide freshly ground cereal and grain to the consumer. Further, the machine should use stone grinding surfaces operating at low speeds to minimize damage to 4 the foodstuffs from heat. Ideally, the machine should be small enough to be installed in the home of the consumer. The prior art discloses no such machine.

SUMMARY OF THE INVENTION The present invention generally comprises a milling machine sufficiently small to be located in an individual dwelling or food market. It employs stone grinding implements rotating at low speed to mill grain or cereal to selected granular size ranging from cracked grain to coarse flour to fine pastry flour. The milling machine operates with high efficiency and low noise output, and grinds the grain without deleterious heat build-up.

The invention is composed of a stationary upper millstone symmetrical about a vertical axis and including a raised central portion. An aperture extending through the central portion is provided with a downwardlyopening conical section coaxial with the vertical axis. An outer annulus is furnished with a horizontal surface which is joined to the concial surface by an oblique medial annulus. The upper stone is slidably mounted on vertical posts which extend upward from the machine base, with springs which bias the upper stone upwardly toward a ring also secured on the vertical posts. The ring includes spaced annular slots for receiving the vertical posts, and subjacent camming surfaces impinging on the upper stone assembly. A handle extending radially from the ring permits the ring to be manually rotated to adjust the vertical disposition of the upper stone by virtue of the camming surfaces.

The invention also includes a rotating lower stone equal in diameter to the upper stone and mounted on a vertical shaft which is driven by a motor. The lower stone comprises-a circular disk coaxial with the upper stone, and a central conical projection extending upwardly therefrom and eccentric to the disk axis. The conical projection extends into the conical aperture of the upper stone, forming a non-uniform chamber the rebetween. The opposed surfaces of the upper fixed stone and lower rotating stone include arcuate depressions to promote the flow of the grain from the feed opening in the top of the upper stone past the conical portion where primary cracking occurs. The cracked grain is fed by the depression and by centrifugal force to the medial annular surface of the upper stone where secondary cracking and grinding occurs, and thence to the outer annular portion where narrow clearances produce fine grinding to reduce the grain to granules.

The size of the granules is preselected by means of the ring and lever, which vary the clearance of the upper and lower stones. The granules are entrapped in a perimetrical housing, secured about the stones, in which circulating air directs the ground grain to a discharge chute extending tangentially therefrom.

THE DRAWING FIG. 1 is a cross-sectional elevation of the present invention.

FIG. 2 is a sectional view of a portion of the present invention, taken along line 22 of FIG. 1.

FIG. 3 is a cross-sectional view of a portion of the present invention taken along line 33 of FIG. 1.

FIG. 4 is a cross-sectional view of a portion of the present invention, taken along line 44 of FIG. 1.

FIG. 5 is a cross-sectional view of a portion of the present invention, taken along line 55 of FIG. 3.

FIG. 6 is a top view of the present invention.

FIG. 7 is a vertical elevation of a portion of the inv ention as seen from line 7-7, of FIG. 6.

FIG. 8 is a detailed cross-sectional view of the air intake of the present invention.

DESCRIPTION OF THE PREFERRED EMBODIMENT As shown in FIG. 1, the grain milling machine which generally comprises the present invention includes an upper milling stone assembly 11. The assembly 11 has a cylindrical plate-like lower portion 12, a levelled raised central stone annulus l3, and a cylindrical metal upper portion 14. An aperture 16 extending through the upper stone includes a tapering opening 17 which forms a hopper, and a downwardly opening conical passage 18 communicating with the opening 17. The lower surface of the upper stone comprises an outer annulus 19 with a horizontal surface, and a medial annulus 21 with an oblique surface joining the conical surface to the outer annular surface. It should be noted that the various portions of the upper stone and its interior grinding surfaces 17, 18, 19 and 21 are all radially symmetrical about a vertical axis.

With reference to FIG. 1 and FIG. 6, the invention includes a base 22 having a plate 23 in which vertical posts 24 are secured in a triangular pattern. Extending radially from the upper stone are three support arms 26 disposed in a like triangular pattern and which include vertical holes therethrough which slidably receive the vertical posts. A helical compression spring 27 disposed about each vertical post impinges on the base and on each support arm to bias the upper stone upwardly. This support system permits the upper stone to be moved vertically as required, yet the arms prevent the upper stone from rotating.

Disposed above the outer portions of the upper stone is a circular adjustment ring 31 with a central hole through which the upper portion of the upper stone assembly extends. The adjustment ring is provided with spaced apart annular slots 32, equidistant from the center of the ring, which receive the vertical posts therethrough. Spaced radially inward from each slot and joined adjacent thereto is an annular camming member 33 which impinges on the corresponding support arm of the upper stone assembly. As shown in FIG. 7, each camming member is subjacent to the adjustment ring with a camming surface 34 oblique thereto.

Secured to each vertical post above the adjustment ring is a sleeve bearing 36 which is translatable on the post. Extending upwardly from each post is a threaded rod 37 on which a washer 38 and a threaded adjust ment nut 39 are secured. It may be understood that the helical springs 27 urge the upper stone upwardly until stopped by impinging on the camming surfaces 34. The camming members are part of the adjustment ring, which is therefore also urged upwardly to impinge on the sleeve bearings. The vertical position of the sleeve bearings is determined by the adjustment nut 39 threaded on the rod 37. Thus the nuts 39 serve as a means of adjustment to limit the upper vertical position of the upper stone assembly.

Secured to the adjustment ring is a radially extending handle 41 provided to facilitate manual rotation of the adjustment ring within the limits of the length of the slots 32. Such rotation in a counterclockwise direction as seen in FIG. 6, causes the camming members to force the upper stone down against the bias of the helical springs, thus lowering the vertical position of the upper stone. Similarly, clockwise rotation of the adjustment ring raises the upper stone.

The present invention is also provided with a lower grinding stone which includes a circular stone disk 42 equal in diameter to the upper stone, coaxial with a drive shaft 43 and joined thereto. The shaft is driven by a motor 44 through a drive belt 45. Joined to the center of the disk 42 is a stone cone 47 which is eccentric to the axis of the drive shaft. The cone 47 is formed from a right angular cone which is truncated along a plane slightly inclined to the right angular base, and cemented or otherwise joined to the disk 42 on the truncated plane. As depicted in FIG. 2, the cone is provided with a plurality of spaced apart, highly defined helical depressions 48. Also, as shown in FIG. 3, the lower stone disk is provided with spaced apart spiral depressions 49. The nature of the depressions is shown in FIG. 5.

The upper stone is similarly provided with spaced apart spiral depressions 51 on opposed surfaces, as shown in FIG. 4. The depressions are similar in crosssection to those shown in FIG. 5, but are oriented in a reverse spiral, as a comparison of FIGS. 3 and 4 makes evident. It should be noted that the clearances between the cone or lower disk and the conical aperture and medial annulus of the upper stone are exaggerated in FIG. 1 for the purpose of clarity.

Extending upwardly from the base is a cylindrical wall 52 spaced apart from the common periphery of the upper and lower stq es and defining an annular chamber 53 therebetween. A flexible circular seal 54 extends between the distal end of the wall 52 to the circumference of the upper stone, sealing the chamber 53 in dust-tight fashion. The disk of the lower stone is provided with a plurality of spaced apart impeller vanes 56 projecting radially from the circumference thereof. The vanes cause an air circulation around the chamber 53 when the lower stone is rotating, carrying ground grain in suspension. A discharge duct 57 communicates with the chamber and extends tangentially therefrom, directing the airflow into a collection container where lowered air velocity causes the ground product to fall out of suspension and to be collected.

At the junction of the lower stone and the drive shaft, a plurality of radial scouring vanes 63 are secured to the shaft to draw air in through channel 61 in the base. As shown in FIG. 8, this airflow passes by bearings 62 which support the lower stone, preventing any accumulation of ground product about the bearings. The airflow from the scouring vanes then passes through passage 64 underneath the lower stone to join the circulating air in the annular chamber 53. Air is also replenished in the chamber 53 through an air intake 66.

To operate the grain mill of the present invention, the motor is actuated to rotate the lower stone. This rotation causes the cone 47 to nutate within the conical aperture in the upper stone. The handle 41 may be employed to rotate the adjustment ring and set the height of the upper stone. This action adjusts the clearance between the upper and lower stones to thereby determine the granular size output.

Grain, cereal or similar foodstuff is poured into the hopper opening 17, from which it falls into the conical passage 18. The nutating cone 47 produces a force feeding effect and initiates primary cracking of the foodstuff. The helical depressions in the cone 47 significantly aid the feeding and cracking process. The cracked grain proceeds down the cone through the increasingly narrow clearance at the lower end of the cone, and is fed centrifugally to the secondary grinding region defined by the medial, oblique annulus 21 and the upper surface of the lower, rotating stone. In this region secondary cracking and primary grinding is achieved, due to the smaller clearance between the fixed and rotating stone, and assisted by the opposed sprial depressions in the opposed surfaces.

Centrifugal force, aided by the sprial depressions, feeds the partially ground grain to the outer annular portions of the stones, where the extremely small clearance between the rotating and fixed stones, which is set by the handle 41, results in the grain being reduced to the desired granular or powder size. The finished product is thrown into the chamber 53, where the air circulation sweeps it up, eventually depositing it in the discharge duct 57. The ground product is then collected in a container. It should be noted that the milling machine is dust-tight, so that no product is lost to the environment. This feature permits the invention to be installed in virtually any location.

It may be appreciated that the unique design of the present invention includes the following important features:

The eccentric cone design produces a greater output of ground grain with less power input;

The staged processing increases efficiency and permits lower rotational speed of the driven stone, thus reducing heat buildup in the ground product;

Instant adjustment through the adjustment ring permits selection of final product granular size with a single lever movement;

Automatic delivery of ground product to container; and

Low noise level and dust-proof design.

We claim:

1. A machine for grinding grain and the like, comprising:

a non-rotating grinding implement,

a rotating grinding implement opposed to said nonrotating grinding implement and spaced apart therefrom, and rotating about a fixed axis, including a nutating member, extending from said rotating implement toward said non-rotating implement;

feed means for introducing the grain between said rotating and non-rotating grinding implement, and said nutating member comprising a conical member joined coaxially to said fixed axis of said rotating grinding implement.

2. The machine of claim 1, wherein said conical member includes a truncated base joined to said rotating member.

3. The machine of claim 1, further including adjustment means for varying the spacing between said rotating and non-rotating grinding implements.

4. The machine of claim 1, wherein said feed means includes an aperture through said non-rotating implement coaxial with said fixed axis.

5. The machine of claim 4, wherein said aperture includes a conically shaped portion opening toward said 6 rotating implement and accommodating a portion of said nutating member therein.

6. The machine of claim 1, further including a peripheral chamber enclosing the perimeter of said rotating implement and said non-rotating implement.

7. The machine of claim 6, further including a discharge duct communicating with said peripheral chamber.

8. The machine of claim 7, further including vane means extending from the periphery of said rotating implement into said peripheral chamber to direct an air-flow through said peripheral chamber and through said discharge duct.

9. The machine of claim 1, further including a base member to which said non-rotating implement is secured in selectively variable spaced apart relationship.

10. The machine of claim 9, further including adjustment means for selectively adjusting the clearance between said rotating and non-rotating implements.

11. The machine of claim 10, wherein said adjustment means includes an annular ring selectively rotatable and secured to said base member with said nonrotating implement disposed therebetween.

12. The machine of claim 11, wherein said annular ring includes at least one camming member extending therefrom and variably impinging on said non-rotating implement in coordination with rotation of said annular ring. 

1. A machine for grinding grain and the like, comprising: a non-rotating grinding implement, a rotating grinding implement opposed to said non-rotating grinding implement and spaced apart therefrom, and rotating about a fixed axis, including a nutating member, extending from said rotating implement tOward said non-rotating implement; feed means for introducing the grain between said rotating and non-rotating grinding implement, and said nutating member comprising a conical member joined coaxially to said fixed axis of said rotating grinding implement.
 2. The machine of claim 1, wherein said conical member includes a truncated base joined to said rotating member.
 3. The machine of claim 1, further including adjustment means for varying the spacing between said rotating and non-rotating grinding implements.
 4. The machine of claim 1, wherein said feed means includes an aperture through said non-rotating implement coaxial with said fixed axis.
 5. The machine of claim 4, wherein said aperture includes a conically shaped portion opening toward said rotating implement and accommodating a portion of said nutating member therein.
 6. The machine of claim 1, further including a peripheral chamber enclosing the perimeter of said rotating implement and said non-rotating implement.
 7. The machine of claim 6, further including a discharge duct communicating with said peripheral chamber.
 8. The machine of claim 7, further including vane means extending from the periphery of said rotating implement into said peripheral chamber to direct an air-flow through said peripheral chamber and through said discharge duct.
 9. The machine of claim 1, further including a base member to which said non-rotating implement is secured in selectively variable spaced apart relationship.
 10. The machine of claim 9, further including adjustment means for selectively adjusting the clearance between said rotating and non-rotating implements.
 11. The machine of claim 10, wherein said adjustment means includes an annular ring selectively rotatable and secured to said base member with said non-rotating implement disposed therebetween.
 12. The machine of claim 11, wherein said annular ring includes at least one camming member extending therefrom and variably impinging on said non-rotating implement in coordination with rotation of said annular ring. 